In a networked environment, such as the Internet or other networks, first-party content providers can provide information for public presentation on resources, for example webpages, documents, applications, and/or other resources. The first-party content can include text, video, and/or audio information provided by the first-party content providers via, for example, a resource server for presentation on a client device over the Internet. The first-party content may be a webpage requested by the client device or a stand-alone application (e.g., a video game, a chat program, etc.) running on the client device. Additional third-party content can also be provided by third-party content providers for presentation on the client device together with the first-party content provided by the first-party content providers. For example, the third-party content may be a public service announcement or advertisement that appears in conjunction with a requested resource, such as a webpage (e.g., a search result webpage from a search engine, a webpage that includes an online article, a webpage of a social networking service, etc.) or with an application (e.g., an advertisement within a game). Thus, a person viewing a resource can access the first-party content that is the subject of the resource as well as the third-party content that may or may not be related to the subject matter of the resource.